Submarine sound system



July 4, 1939.

,1. R. wEs'r susnfxARINE scum; SYSTEM Filed June 29, 1936.

Hna/0 R565/ VER Jamzbmu@ d Mba@ ZTTORNEY l' BT81111811 July 133s meats 2,164,858 sua so sys'ra'nr Jarold R. West, New York, N. Y., assigner to Roger Williams, New York, N. Y.

Application .rime as, 193s, serial No. smet transmitting sounds through the body of a liquid. More particularly this invention embraces apparatus and methods for transferring vibratory sound .energy from a producer thereof into a body of liquid.

I'his invention discloses a method of coupling asound producing unit such as an electro-acoustical unit to a body of water, so that sound waves l0 of comparatively great intensity will be set up within this body of water,

One object of this invention is to produce an electro-acoustical transmitting device, adapte'd to set up submarine oscillations, which shall be 13 comparatively simple and cheap to construct,

and which utilizes materials and' parts readily available.

Another object of this invention is to afford means for ,readily transferring a large amount of sound energy to a body of water.

Another. object of this invention is to aiford ready means of transmitting intelligence by means of acoustical signals from one point in or on a body of water toa another point in or on the same body of water. f

A still further object of this invention is to afford a simple and cheap means of coupling the output of the ordinary telephonie loud speaker unit to a body of water. 1

Yet another purpose of this invention is to afford means which may readily be attached to vessels in motion or at rest, without the necessity of making special apertures in the hulls thereof, and which may be supplied withsignalling en- A ergy from the radio telegraph, or radio `telephone equipment usually present on such vessels.

Another purpose of this invention is to afford means for readilyemitting signals from a submerged vessel of the submarine type either for normal communication purposes, or in case of emergency.

Yet another object of this invention is to supply. music and speech, such as received from radio or wire broadcasting o r from a phonograph ,45 pick-upto a body of awter so that bathers or swimmers therein may readilyv listen to such music or speech. f A still further .object of this invention is to afford means for communicating' with persons 50 submerged in a body of water, such as persons learing to ,Ns-wim, or swimming beneath the surface of suchwater. 1

'This invention is directed to an eflicient cheap andasimple coupling-"unit which will transfer 55 zsound from a reproducing unit to a body of The present invention relates to the art-of.

water. Broadly speaking, this invention consists of an elongated tube of suitable material which is immersed in a body of water and which has the portion thereof lying beneath the surface of water suiciently impervious thereto so .5 that immaterial amounts of water or none at all" will enter the interior of this hollow tube. At one end of the tube is affixed asound reproduc- -ing unit, such as a loud speaker unit, which', when actuated, sets u p oscillations in the air present :l0 in the interior of the tube. The sound oscillations thus set up are transferred through the walls of the tube to the water surrounding it.

I have found that, in distinction from the practice previously used in the art of submarine 15 signalling, sound energy may be very eiliciently Y transferred from a column of air to a body of water, by means of lateral transmission through the walls of a tube of elastic material which forms a boundary between the column of air and "20 the water.

The hitherto employed devices, transferred oscillating energy into a body of water by causing a flexible diaphragm of some nature to beA actuated by the' sound producing unit. Many de- $5 vices have directly coupled a loud speaker diaphragm oroscillating amature to a diaphragm which formed the boundary between the water and air. My invention differs widely from these devices in that it sets up oscillationsin a col- `30 umn of air and transfers these vibrations in -a lateral fashion fromthis column of air into' the surrounding liquid. In the'devlces of the. prior metal and the like. 4.

It has been found that the devices employing moving diaphragms have encountered `great-diilculty in eiiciently transmitting oscillations to such diaphragms. Such diaphragms are Vheld at their peripheries andv accordingly their freedomof motion varies widely at different points thereof. Various artiiices have been proposed to ameliorate this diiculty, such as supplying energy to the diaphragm at a plurality of points.

, for example, to an annular portion of the diaphragm.

It has likewise been proposed to' interpose an air chamber between the oscillating unit and the coupling diaphragm. This' invention distin-y guishes from all these devices by using an air chamber whose walls are constructed. of a very elastic material such as soft rubber and which will transfer the oscillations directly therethrough without theemployment of an intermediary coupling unit suohas a diaphragm.

'I'o more clearly explain my invention, I refer to. the drawing hereunto attached where:

Fig. l is .an elevation in cross section, and partly schematically, showing one form of my invention.

Fig. 2 is an elevation of the upper portionof another form of my invention, using a plurality of sounds producing units.

ment of my invention, designed to be completely submerged in a liquid.

In Fig. 1, a loud speaking unit is shown at l0, including an outside containing shell upon the end I2, of which is mounted a permanent magnet I3, wound with a coil |4, whose terminals Il, I5 are connected to a source of electrical oscillations, corresponding to the acoustical oscillations to be transferred to the water. A flexible diaphragm I6, of suitably magnetic material is held against a supporting member at its periphery, by the attractionof magnet I3. The lower end of unit I0' is passed through an aperture in closure member I8, which member may be of wood, metal, or other suitable material.

lUnit Il opens at its lower extremity into chamber ,Y Il, which is formed by the closure of a hollow tube 2l, at both ends.- 'Iheclosure at the upper end is accomplished by member I8V and the closure at the lower end may be accomplished by 'another similar member 2|. The tube 20 is preferably fonnedof soft rubber or other material of similar 4acoustical characteristics, and closure members Il and 2| may be held within the ends of tube 2l yby being forced therein against the natural elasticity of the walls of this tube. Tube 2| is submerged in a body of water 22. While! have here shown a certain type o sound reproducing unit, it is to be understood that any suitable form of auch unit may be used. For example, instead of the electro-magnetic type,the electro-dynamic type may conveniently be employed. f

While not eonnningmyself to any particular dimensions, I have found that for small types oi' water such as swimming pools and the like, and for sound reproducing units supplied with-only a few watts of energy, a piece of soft rubber hose -about 10 feet in length and about. 2% inches in v lower portion enters through closure member I3 into tube 2l in exactly 'the same fashion as shown in Fig. l. The electrical coupling of units 3l and 3| by means of conductors 34, may be of the series fashion here indicated, and energy may be rated into the radio receiver itself.

any given case is dependent upon well known factors, including the relative impedance of theI power source and the units. Tube 20 is closed at the lower end 23' by vulcanization.

'In Fig. 3, the antennae 4l), feeds picked up broadcast signals to a radio receiver 4| which may be supplied with a suitable ground connection, 42. The output of receiver 4|, if not al unnecessary in many Cases, 01' may be DCOI'DO- l I have also shown a microphone 45, coupled by suitable conductors 46, to the input of amplifier 43. By suitable switching means (not shown) the amplifier 43 may be coupled either to the microphone or to the receiver. It is to be'understood that if amplier 43 is not used, the microphone 45, may be coupled into the circuit of the receiver 4|, so as to raise the level of energy supplied by the microphone to a degree suitable for feeding sound producing unit 44. I

The sound producing unit is coupled to the soft rubber tube 20, by means similar-'to those shown in Fig. l, and the walls of tube 20 then transfer the sound energy into the surrounding water 22. While this transfer takes .place over the entire submerged length of the tube 20,`I have indicated diagrammatically the sound waves proceeding from a single point 45 of the tube 2l, by means of concentricarcs 41, and at 43, I have shown the ear of a listener upon which ear these sound waves-may impinge. V

In Fig. 4, I show a. comparatively rigid and impervious casing 50, which is closed at the top by means of a removable cover 5|, afllxed thereto by bolts 52, located around its periphery. Thev point of junction between cover 5| and casing 5|! may either be ground to a close t, or a suitable' gasket may be interposed between these two members. Cover 5|, may be provided with a suitable ring bolt 53, for the purpose of lowering and raising the entire unit with respect to the body of water in which it is submersed. The

bottom of casing 50, is supplied with a' projecting nipple 54, over which soft rubber tube 20 may be firmly clamped .by means such as an ordinary hose oclamp 55.

The bottom lof tube 2li may also have its cio, sure member 2| held firmly therein by another clamp 56, or may have its ends vulcanized togethel as shown in Fig. 2.

Within casing 50 is placed loud speaker unit 51, 4'

which may be'threaded into the upper end of a passageway 53, extending through nipple 54, and arding an air passage for the sound to pass from unit 5l, into air chamber I3.

Unit 51 is shown as being of the dynamic type and two conductors 60, 6|) supply energy to the voice coil thereof by means of binding posts 5|, 3|. The field -energy forv this speaker may be supplied by conductors 62, lthrough binding posts 33, 53. The four conductors thus leading from unit 5l may be brought out of casing 5l by means of a pipe, which-extends through cove 5|, and is Vmade of a length sulcient to reac above the surface of 'the liquid in which the entire structure is submerged.

Pipe 34, is conveniently lined with rubber insulation 55. I have found it however, of great importance that pipe Bl'bemade of sufficient cross section so that the conducting wires passing the functioning of the to be more efficient,

probably due to the reduction of the back pressure effect noticeable when such units are completely enclosed. The assembled structure shown in this gure is waterproof and may be submerged to any desired depth, provided only that pipe 64 reach to the surface. Y

The manner in which the various embodiments of my invention function has already been described and the details thereof will be apparent to those skilled in the art.

Where several units are employed as in Fig. 2, it is highly desirable thatthey be so connected that their respective sound outputs shall be in phase with one another, as otherwise a great loss of eiliciency and a great amount of distortion may be experienced..

While I have described the reception of sound from my transmitting apparatus, as being accomplished directly by the human ear, yet it is to be understood that, especially for purposes of commercial signalbing, the distance of transmission and/or ease of reception may be augmented by the employment of ancillary devices at the receiving end. One example of such an arrangement is the use of the microphone which may be either submerged in the water, or placed at the upper end of an air lled tube similar to that employed at the transmitter.

It is to be understood that while I have shown a radio receiver or a microphone feeding the reproducing unit of my system, any other suitable means for feeding this unit may be used, such as energy derived from wire broadcasting services or phonographic pick-ups.

fIt is to be noted that my invention distinguishes from prior devices by using the molecular vibration of the entiretube walls as a sound transfer v or coupling means, rather than by the mass vibration of any diaphragm-like member as a whole.4

I rclaim:

1. A device for transferring speech and music from air into water, including an elongated tube of elastic material substantially submerged in water and filled with air, the walls of said tube constituting a homogeneous medium for the propagation of sound energy laterally therethrough substantially wholly by molecular vibration of said walls, rather than by mass vibration thereof, and an electro-acoustical transducer located at one end of said tube, said transducer including a vibrating diaphragm substantially completely closing one end of said tube and means extending from one side of said diaphragm into the free air above said water, wherebythe air in said tube is subjected to the pressure waves .'rom one side of said vibrating diaphragm, and whereby substantially no back-pressure effects upon the other side of said diaphragm hinder the motion thereof so as to cause acoustical distortion.

2. A device for transferring voice frequencies from air into water, including an elongated tube of elastic material, means for closing both ends of the tube, one of said closure means comprising one side of an imperforate acoustical diaphragm, means for vibrating said diaphragm at voice frequencies and means for keeping substantially normal atmospheric pressure upon the other side of said diaphragm, whereby differing pressures of air can exist upon opposite sides of said dia.- ph'ragm.

JAROLD R. WEST. 

